What Is a CBC Test?

A Complete Blood Count (CBC) is one of the most commonly ordered blood tests. It gives a broad snapshot of your overall health by measuring the different cells that make up your blood.

What it measures

A CBC typically reports on red blood cells (which carry oxygen), white blood cells (which fight infection), platelets (which help blood clot), along with related values like hemoglobin and hematocrit. Together, these numbers can point to conditions such as anemia, infection, or clotting issues.

When is it ordered?

Doctors often include a CBC as part of a routine health checkup, or to investigate symptoms like fatigue, unexplained bruising, or recurring infections. It's also commonly repeated to monitor existing conditions or treatment.

Preparation

A CBC usually doesn't require fasting, but your doctor may ask you to fast if it's being done alongside other tests. Always confirm preparation instructions for your specific set of tests before your appointment.

This article is for general information only and isn't a substitute for medical advice. For interpretation of your specific results, please consult a qualified healthcare professional.